16 Reasons Why Your John Deere Mower Won’t Move Forward Or Reverse

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If your John Deere mower won’t move forward or reverse, it might be due to a borken or loose drive belt, or a missing idler arm spring.

In this article, we share 16 possible causes of the mobility problem, and quick fixes to get your mower working efficiently again.

But before we jump right into that…

Some of the reasons why your John Deere rmower won’t move forward or reverse include:

  • Defective drive belt
  • Missing idler arm spring
  • Drive release handle not in operating position
  • Air in the hydraulic system
  • Lack of regular tune-up

1.  Defective Drive Belt

The drive belt is an important component for moving your John Deere riding mowing machine to the forward position.

A worn belt may cause the mower to move sluggishly but it won’t move at all if it is broken.

Fix: Change the defective drive belt.

Note: It is important to check the manual to take off the mower deck and then the belt. You can also seek the help of a professional to help fix the issue.

2. Bypass Control Lever Not In “Engaged” Position

If the bypass control lever isn’t in the engaged position, the John Deere mower may fail to move, affecting the operation and functionality of the mower.

Fix: Ensure that the bypass control lever is in the “engaged” position (pulled up and pushed in). 

You can contact your local authorized servicing dealer for evaluation and repair if the problem persists.

3. Missing Idler Arm Spring

The idler spring is responsible for placing tension on your mower’s drive belt. 

If you notice that there is no tension on the drive belt, the idler arm spring may be missing. This affects the mobility of your  John Deere riding lawn mower.

Fix:It is best to replace the spring if it is broken

4. Defective Tensioner Pulley

Tensioner pulleys are often made from hard plastic and have a bearing in the center. 

If the pulley breaks or the bearing fails, the John Deere riding mower may fail to go forward.

Fix: Inspect the pulley and replace it if it is defective. It is also important to grease the tensioner arm pulley so that it will not seize up.

5. Missing Key in Axle

A missing key in your mower’s axle may cause the lawn mower not to move. It may occur that the key fell out of the axle while trying to change the tire of your riding lawn mower. For your wheel to move, it is best to install it.

Fix: Install the missing key in the axle. 

6. Drive Release Handle Not in Operating Position

The drive release lever allows your John Deere riding lawn mower to roll in a free manner. The drive release handle also enables the mowing machine to move in a forward position. 

This component can be in the form of a lever, push/pull button and knob.

If the drive release handle is not in the operating position, it may stop your lawn mower from moving.

Fix: Ensure that you check the manual to locate the drive release handle and make sure that it is in an operating position. 

7. Low Hydraulic Fluid Level in a John Deere Riding Mower

If you run the transmission with low or old hydraulic oil, it may cause your riding mower to develop mobility issues.

Fix: To keep the transmission system of your John Deere riding mower running at an optimal level, it is advisable to ensure consistent hydraulic oil change at intervals based on the recommendations of John Deere.

You also need to change the hydraulic oil and filters at the recommended intervals.

If you notice that the hydraulic oil is low, you need to add more hydro oil till the level of the fluid gets to the full level when the hydraulic oil is cool.

8. Air in the Hydraulic System

It is necessary to bleed the air out of the system after changing the hydraulic fluid. Air in the system may make the mower not move.

Fix: Follow John Deere’s procedures for changing the hydraulic fluid and bleeding air from the system in the owner’s manual.

9. Hot Hydraulic Fluid

Hot hydraulic fluid may also be one of the reasons why the riding mower won’t go forward. 

When you operate your John Deere riding mower with a low fluid or bad hydraulic fluid, the oil will fail to lubricate the hydraulic system well and this results in overheating and increased friction of the fluid.

Fix: It is advisable to take the mower to a local repair dealership to fix the issue.

10. Carburetor Failure

A carburetor can blend fuel and air to create a combustible mixture for the engine cylinder.

Your John Deere riding mower may not move forward or reverse due to carburetor failure.  This can be a result of gummed-up gas that will clog the carburetor.

Fix: The best way to fix this is to replace the bad carburetor with a new one

11. Clogged Air And Fuel Filters

The air and fuel filter of your John Deere mowing machine may get blocked and affect the operation of your mower. 

A blocked fuel filter prevents the gas from flowing to the engine in adequate supply.

A clogged air filter can also cause your mower engine to overheat. If these two components are clogged, it may prevent the John Deere riding mower from going forward or reverse.

Fix: Replace clogged fuel and air filters.

12. Transmission Failure

Issues related to the mower’s transmission can result in the inability to shift gears, causing the mower from going forward or reverse. 

It is also possible that the mowing machine can get stuck in one gear. These issues can be a result of leaks in fluid reservoirs or transmission lines.

Fix: It is best to seek the help of a professional to fix the issue for you. 

13. Brake Issues

A John Deere riding lawn mower may fail to go in forward or reverse due to brake issues. A user commented that brake problems caused the mower to smell like the belt is heating up. In this case, the wheels may spin in the opposite direction.

If the brake pins do not work well, the brake of your John Deere riding mower may get stuck, affecting the functionality of the riding mower.

Fix: Remove the brake and clean it up. It is also important to do a light brass brushing and place it back in its normal position. 

14. Lack of Regular Tune-Up

The engine of the John Deere riding mower may not move forward or reverse due to lack of regular tune-up.

The carburetor of your mower will not be able to get adequate air to mix with gas for combustion if the air filter is jammed with debris, causing the mower to sputter or not to move.

Fix: To increase the efficiency of your engine, a kit is important to:

  • Replace oil and air filters
  • Replace the engine oil. 

15. John Deere Riding Mower is Stuck in Gear

The riding mower may get stuck in gear due to some factors such as operator error in adjustments or wear and tear. 

There are some instances where you adjust the brake tension instead of replacing worn pucks or brake disks. This will hinder the gear shifting process.

Other likely causes may be dysfunctional brake pins or worn parts connected to the transaxle.

Fix: It’s advisable to hire a professional to help you troubleshoot this problem.

16. Hydraulic Fuel Leak

A customer complained that the lines were leaking oil, preventing the riding mower from moving.

You can notice this issue when your John Deere riding mower makes jerky or sluggish movements. In addition, you may also experience a burning smell or oil spills.

Fix: The first thing to do is to identify the source of the leak.

Check for worn/cracked/broken crankcase gaskets and gasket seals and replace them if they are in a bad condition. 

How Does John Deere Hydrostatic Transmission Work?

The hydrostatic transmission of your riding lawn mower can be used to transfer power from the motor to the hydraulic pump to run the wheels.

The pumps of some John Deere mowers make use of a liquid pressure to operate them.

If you notice that our John Deere hydrostatic transmission isn’t working well, you may need to check for poor drive belts, broken springs, stuck gear and dust and air in the hydraulic system. 

Conclusion

If you notice that your John Deere riding mower won’t go forward or reverse, the first step to take is to know the causes.

Some of the possible causes include missing key in axle, air in the hydraulic system, missing idler arm spring, bad tensioner pulley and worn drive belt.

Read our recommended fixes to get your John Deere riding mower working again. It is advisable to seek the help of a professional if the problem persists.